In photolithography processing in manufacturing, for example, a semiconductor device, for example, resist coating treatment of applying a resist solution onto a semiconductor wafer (hereinafter, referred to as a “wafer”) to form a resist film, exposure processing of exposing a predetermined pattern on the resist film, heat-processing of accelerating the chemical reaction in the resist film after the exposure, and developing treatment of developing the exposed resist film are performed in sequence to form a predetermined resist pattern on the wafer.
As a method of applying the resist solution onto the wafer, for example, a method called a spin coating method has been conventionally used. The spin coating method is a method of suction-holding a wafer on a disk-shaped holding member called a spin chuck, discharging a resist solution in a solution form onto an almost center of the wafer, and then rotating the spin chuck. By rotating the spin chuck, the resist solution supplied on the center is spread by the centrifugal force and applied over the entire front surface of the wafer.
To preferably implement predetermined photoplithography processing, it is important that the resist film applied on the wafer has a predetermined film thickness. Hence, conventionally, the film thickness of the resist film on the wafer is measured before the predetermined pattern is exposed on the resist film, so that when the thickness exceeds a predetermined permissible value, for example, the number of rotations of the spin chuck in the resist coating unit which applies the resist solution is corrected based on the measurement result (Patent Document 1).
[Patent Document] Japanese Patent Application Laid-open No. 2001-196298